As you may already know the vertical bar located on your Ubuntu left side is called “Unity launcher”. It allows you to easily launch programs and access workspaces, removable devices, the trash bin,mounted devices etc… By default the icons located on the Unity launcher are very large so if you work on a small screen in may take a lot of valuable screen space, so, in such case you may want to decrease the size of the icons (on increase them, if you have a large screen or multiple screens). This is so easy to be done, and in this tutorial I will explain how to do that actually.
First, you will need to click on the System Settings icon on the Unity launcher.
If the System Settings icon do not appear on the Unity launcher you can also click the gear in the upper-right corner of the screen on the top bar and select System Settings.
Once the Settings dialog box open, click Appearance in the Personal section.
On the next screen (the Appearance screen), make sure to select the “Look” tab.
On the same screen you should see a slider which is located in the bottom-right corner. You can use that slider for changin the Launcher icon size. Drag the marker either direction to increase or decrease the icon size on the Unity launcher. You can see the results immediately on the Unity launcher as you change the size.
And as you can see from the next image, the icons have been made smaller.